When objects are to be sorted or checked, if they are elongated in one dimension it is highly desirable that they all be aligned in the same general direction, e.g., with their elongated axes parallel. This is particularly the case when such objects need to be sorted and defective objects rejected.
The invention is particularly, although not exclusively, useful in relation to objects which are substantially cylindrical and, in particular, of an elongated cylindrical nature, such as sausages. However, the objects need not be truly cylindrical and more conically shaped objects such as carrots can also equally be aligned by adopting the principles of the invention.
Presently known systems use a vibratory conveyor on to which such objects are dropped, and their alignment is achieved by providing within the top surfaces of the conveyor, grooves which extend lengthwise in the direction of advance of the conveyor. The elongated objects then progressively align themselves and drop into these grooves as they advance along the vibratory conveyor.
The problem with such a simple arrangement however is its overall capacity. Thus the speed of advance of a vibratory conveyor is relatively low and is in any case limited by the necessity to allow quite a long length of conveyor or, in other words, time for the objects to become aligned and to fit into the elongated grooves. In practice, this means that one needs to use a very wide vibratory tray to cope with the amount of material to be laned, but even then there are problems in that sometimes the objects lay upon one another in the grooves, known as a double stacking problem, and in any case the speed of advance is still very slow.
To overcome the problem of double stacking, it is normal to have a number of vibratory conveyors, usually three, positioned one after the other with the aligned objects from the first conveyor falling on to the second, and from the second on to the third, the hope and expectation here being that eventually along the overall length of the combined conveyor, the double stacking will be avoided because at some stage, a second or third item laying on a first will fall back and rest at the bottom of a groove on its own. Such an arrangement can reduce or avoid double stacking but does nothing to increase the speed of sorting.
Attempts to increase the speed have included the provision of upstanding pins on the vibratory conveyor which act as something of a block to objects which reach the pin in a direction somewhat transverse of the elongated grooves. Then, provided the object hits the pin away from its centre of gravity, the pin will tend to cause the object to align as it passes the pin, but there can still be problems of blockage in the event that there are a relatively large number of such objects which are not aligned by the time they reach the pin.
The invention has therefore been made with these problems in mind, and aims to provide apparatus and a method for aligning such objects far more quickly and accurately.